Serena Williams lost 6-0 6-2 to rising star Simona Halep on Day 3 of the 2014 WTA Finals.
The win placed the No. 4-ranked Canadian in a better position to progress to the semi-finals of the season-ending tournament from the Red Group, as she presently leads with a 2-0 record.
Halep, who has never won the American or any other Top 3 opponent prior to Wednesday, needed 20 minutes to storm to a 6-0 opening-set win.
It took 37 minutes for the 33-year-old American to earn her first match point at 1-2 in the second set but Halep stepped up her game, saving all six break points carved out by Williams to secure her first win over the world number one after four meetings in straight sets.
The defeat also marks the first time the Top seed failed to win more than two games since losing 6-1 6-1 to Joannette Kruger in Oklahoma City- then 16- in 1998.
The win increases Halep’s WTA Finals record to 2-0 and ends the two-time defending champion’s 16-match winning streak.
Williams will probably have to win her final round-robin match against Eugenie Bouchard to advance from the Red Group.
In the other contest in the Red Group, 7th seed Serb Ana Ivanovic dropped one game in the opening set against Canada’s Eugenie Bouchard en route to a 6-1 6-3 win- her first in Singapore.